Golf Course Management

NOV 2012

Golf Course Management magazine is dedicated to advancing the golf course superintendent profession and helping GCSAA members achieve career success.

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cutting edge Research in progress acidification processes at the green's surface. Our understanding of how supraoptimal root-zone pH influences Penn A-4 root growth is limited. A greenhouse study evaluated root growth, viabil- ity and distribution of Penn A-4 receiving ample maintenance fertilization but maintained under multiple root-zone pH levels (5-7.5). Also, root- zone samples collected from field studies of greens in 2007, 2011 and 2012 were analyzed for soil pH, root-length density, specific root length and spe- cific fork number. A metadata analysis approach will generate a more specific soil pH range for optimal root growth of Penn A-4 creeping bent- grass maintained as greens. — Derek Pruyne and Maxim Schlossberg, Ph.D. (mjs38@psu.edu), Penn Photo by M. Flessner Glyphosate-tolerant perennial ryegrass Replay and JS501 perennial ryegrass cultivars population inhibition) values, obtained at 6 WAT from visible injury data: I50 = 2.28, 2.36, 0.72 and 0.75 pounds glyphosate/acre for Replay, JS501, Caddy Shack and Top Gun II, respectively. Replay and JS501 had similar glyphosate tolerance, up to four times greater than Caddy Shack and Top Gun II, across rating dates and data types. — Michael L. Flessner; J. Scott McElroy, Ph.D. (jsm0010@auburn. edu); and Glenn R. Wehtje, Ph.D., Auburn University, Auburn, Ala. Root-zone pH and Penn A-4 root growth Root-zone pH influences nutrient availability Photo by D. Pruyne Teresa Carson 98 GCM November 2012 and root growth during establishment and main- tenance of Penn A-4 creeping bentgrass greens. The optimal pH range for creeping bentgrass is considered 5.5-6.5, but sand root zones of greens across the Mid-Atlantic and Midwest regions fre- quently contain calcite and are buffered to higher pH values. Further alkalinization, via topdressing sand and/or irrigation water inputs, offsets natural have been bred for tolerance to glyphosate. Green- house experiments were conducted to compare glyphosate tolerance of Replay and JS501 to that of cultivars without enhanced tolerance (Caddy Shack and Top Gun II) through log-logistic dose- response analysis. Plants were established from seed in native soil, treated at 3-4 tillers, and mowed at 3 inches at 2, 4 and 6 weeks after treatment (WAT). Glyphosate was applied at 0 (nontreated) to 5.6 pounds ae/acre across 13 treatments. Each treatment was replicated four times; the entire experiment was repeated in time. Visible injury was assessed relative to the nontreated at 2, 4, and 6 WAT. Cultivars were compared using I50 (50% State University, University Park, Pa., and Chase Rogan, Pure Turf Consulting, Pittsburgh, Pa. Golf Course Environmental Profile Pesticide Use Prac- tices on U.S. Golf Courses is report the fifth in GCSAA's Golf Course Environ- mental Profile, a data collection project that provides new insight into the property fea- tures, management practices and inputs associated with golf courses across the United States. The objectives of the survey described in this report were to quantify pesticide use and investigate pesticide use practices and pest man- agement tactics at golf facilities in the U.S. and its agronomic regions. This report provides an accurate portrayal of pesticide use practices on golf courses in the U.S. It establishes a baseline that can be compared to data from future surveys to identify change over time. The report will be released in December on the GCSAA website, a scientific article about the survey will be pub- lished in Applied Turfgrass Science, and an article about the survey will be published in the Janu- ary issue of GCM. This research is funded by the EIFG and The Toro Giving Program. — Greg Lyman (glyman@gcsaa.org), director, Environmental Programs, GCSAA Photo by T. Royer GCM Teresa Carson (tcarson@gcsaa.org) is GCM's science editor.

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